/*
package cn.jdemo.jdk8.customStream;

public interface Stream<T> {

    <R> StreamImpl<R> map(Function<R, T> mapper);


    <R, A> R collect(Collector<T,A,R> collector);

    static <T> StreamImpl<T> emptyStream() {
        return StreamImpl.<T>builder().empty(true).build();
    }
}
*/
